1. Field of the Invention
The present invention relates to a bio molecular detection apparatus and a method thereof, and more particularly, to an apparatus and a method of measuring electrical characteristics of an inductance device and a capacitance device before and after the hybridization of a capturing probe and a sample to detect whether or not a biochip is coupled with the sample.
2. Description of the Related Art
A biochip refers to a biological microchip for analyzing a gene expression way, a distribution pattern and a mutation by arranging and attaching biomolecules, such as DNA, DNA fragment and RNA having the known sequences, on a small solid substrate formed of glass, silicon or nylon.
The biochip immobilizes materials, which function as capturing probes to search for specific gene information contained in a sample, on its surface. If the biochip reacts with the sample to be analyzed, the capturing probes of the biochip are respectively hybridized with materials of the sample. By detecting and interpreting whether or not the sample is coupled with the probes, information on the materials of the sample can be concurrently obtained.
Examples of technology relating to the biochip are a probe attaching and immobilization technology, a signal detecting technology, information processing technology and the like.
Examples of signal detecting method currently used are a laser-induced fluorescence detecting method, an electrochemical detecting method, a mass detecting method, a mechanical detecting method and the like. In the laser-induced fluorescence detecting method which is most widely used, a fluorescent material is coupled with a sample. After the coupling reaction of the capturing probe and the sample, a result of the coupling reaction is detected using a fluorescence detecting apparatus to optically determine whether or not the capturing probe is coupled with the sample. However, before the coupling reaction of the capturing probe and the sample, the laser-induced fluorescence detecting method requires a preprocessing reaction for coupling the fluorescent material with the sample. Therefore, the laser-induced fluorescence detecting method has a drawback in that sample loss or contamination can be caused. Further, the laser-induced fluorescence detecting method has a drawback in that it needs a complex optical detecting system for detecting whether or not the capturing probe is coupled with the sample after the coupling reaction of the capturing probe and the sample, and a high-priced measurement equipment. Further, the laser-induced fluorescence detecting method has a drawback in that it is difficult to accomplish miniaturization, and a digitalized output cannot be viewed.
In the electrochemical detecting method, it is detected whether or not a capturing probe is coupled with a sample by using an electrochemical reaction, that is, a reduction and oxidation reaction of other chemical materials on an electrode. The coupling reaction of the capturing probe and the sample is performed at the electrode. This method has a drawback in that it has a less detection capability than the fluorescence detecting method.
In the mass detecting method, an inter reaction between a capturing probe and a sample is electrically signalized and detected. As a typical example, there is an electrochemical Quartz Crystal Microbalance (QCM) detecting method for measuring a frequency variation depending on a mass of the capturing probe immobilized on quartz, which vibrates at a high frequency.
In the mechanical detecting method, a minutely assembled cantilever is used to measure a coupling strength between molecules before and after a capturing probe is coupled with a sample. However, this method has a drawback in that additional equipment such as a laser equipment is required to very minutely measure a refraction of a cantilever beam.